Electrodynamic telephone handset



OLHKUH H00! Sept. 20, 1949. c, BECKMAN ETAL ELECTRODYNAMIC TELEPHONEHANDSET Filed Sept. 10, 1945 lllllo Ill V INVENTORS N A m M n w 6 T c MA EA. 2 6/ w Patented Sept. 20, 1949 ts h'UUl ELECTRODYNAMIC TELEPHONEHANDSET Carl Beckman, Montclair, and Irving Zambakian, Bloomfield, N. J.

Application September 10, 1945, Serial No. 615,258

2 Claims. 1

This invention relates to improvements in telephone systems such as areused to communicate sound from a point of origin to a point removedtherefrom.

In the conventional telephone systems an external source of power isincorporated in the telephone circuit and is essential for the actuationof the telephone instruments and for the reproduction of the sound wavesin the receiving telephone.

Attempts have been made in the prior art to provide telephone systemsdispensing with an external source of power, by connecting thediaphragms of sending and receiving instruments with a taut cord or thelike. Such systems have been found to be ineflicient and to have theobvious objection that the telephone instruments had to be held taut toavoid damping the sound waves.

The object of our invention is to provide a telephone system wherein noexternal source of power is used, wherein the telephone instruments maybe freely held and moved in use, and wherein the transmission of soundis obtained in an eflicient, accurate and faithful manner.

A further object of the invention is to provide a telephone system whichis self-suflicient, is powered by the sound waves to be transmitted andwherein the sound is transmitted and faithfully reproduced in telephoneinstruments of novel design.

Further advantageous objects attained by the use of our invention willbecome apparent from a consideration of the following description andthe accompanying drawings, in which:

Fig. 1 is a side elevational view of a telephone unit embodying ourinvention,

Fig. 2 is an enlarged, fragmentary sectional view thereof, taken on line22 of Fig. 1,

Fig. 3 is a horizontal sectional view, taken on line 3--3 of Fig. 2,

Fig. 4 is a diagrammatic view of a principle utilized in carrying outour invention,

Fig. 5 is an elevational view of a telephone system embodying ourinvention,

Fig. 6 is a diagrammatic view thereof, and

Fig. 7 is a diagrammatic view of another form of our invention.

In the drawings, Figs. 1-6 illustrate a form of our invention whereinthe telephone unit U of the system embodying our invention comprises atubular hollow casing l0 terminating in sound chambers II and I2 withwhich casing I0 is in open communication. Chamber H is provided withsound transmitting means generally designated as 32, chamber l2 beingprovided with an outer cap or ring 28, preferably of resilient material.

Transmitter 32 comprises permanent magnet members l3, l4 and I4 fixed tothe chamber H by any suitable means as by rivets 33, so that the memberI3 will be medially implied in said chamber with the free end N thereofspaced from the free ends S of members l4, H which are arranged inradially spaced relation thereto. The magnet members I3, l4 and N arepreferably made of a highly magnetized alloy which will provide apermanent intense magnetic field |5 around the free end N of member l3,said field 5 being defined by the magnetic lines l6, l1 flowing radiallyfrom member l3 as shown in Fi 4.

A diaphragm 3|, preferably made of paper, plastic or other suitablenon-metallic material, is peripherally held in the chamber I adjacentthe open end thereof by a screw cap 28 or the like; gasket 36 ispreferably interposed between the cap 28 and diaphragm 3|. A wire coilI8 is fixed to an open spool 30 medially mounted on the diaphragm asshown in Fig. 2. The coil 30 is thus positioned in the intense magneticfield l5 of the permanent magnet members so that in reciprocating insaid field responsive to the vibrations of diaphragm 3| (when words orother sounds are directed against the diaphragm) pulsations of currentwill be induced in the coil It as will be apparent to those skilled inthis art. The opposite ends of coil l8 are connected to lead wires 25,26 directly, or, as shown in Fig. 2, by connecting said lead wires toinserts 23, 24 molded in or otherwise afflxed to the chamber H. The freeends I9, 20 of coil I8 are connected to said inserts in any desired orconvenient manner, as by baring and positioni g said ends atop foilstrips 2|, 22 secured to e diaphragm 3| adjacent the periphery theizaof,(or by securing the same to said foil strips) for contact and registrywith the inserts 23, 24 on assembly of the parts as shown in Fig. 2. Thechamber II and the diaphragm 3| may be provided with complementarykeying means 34 to assure the proper registry of the parts on assembly.The structure described and shown in Figs. 1 and 2 provides a telephoneunit U adapted to be manually or otherwise held with the speaking ortransmitting end adjacent the users mouth; the cable C containing thelead wires 25, 28 of the wire coil carries the current induced in thecoil by the vibrations of diaphragm 1|.

Diaphragm ll may likewise be vibrated responsive tho-current flowinginto coil l8 through the cable C to set up sound waves in the unit Uwhich will flow through the tubular hollow casing 10 to the listening orreceiving chamber 12 and to the listeners ear. In the form shown inFigs. 1-6 the chamber I2 is a hollow member as generally indicated at21.

The unit U is a complete telephone unit; by providing a unit U ofidentical structure therewith, and connecting the wire coils of thetransmitter members 32 of units U, U as shown in Figs. 5 and 6, we haveprovided a complete telephone system for communicating sound betweentelephone units U and U, utilizing no external source of power for thatpurpose; the vibrations of diaphragm 3| in one telephone unit inducecurrent carried by cable C to the other unit to reproduce the sound inthe latter. We have found that the arrangement described provides aneflicient telephone system which does not require the use of an externalsource of power.

In the arrangement shown in Fig. 7, the chamber l2 of each unit in thesystem contains a transmitter member 35 which is a duplicate oftransmitter member 32 in chamber II. In the system shown in Fig. 7, asin that of Figs. 1-6, no external source of power is used between theunits U and U, the vibrations of the diaphragm in member 32 of unit Ubeing reproduced in member 35 of unit U (and vice versa).

The parts described may be made of any suitable material; the uses ofthe system are many and obvious.

The telephone units shown in Fig. 6 are connected in parallel, whilethose in Fig. 7 are connected in series.

Having thus described our invention what we claim as new and desire tosecure by Letters Patent, is:

1. In a telephone system including a pair of telephone units, eachcomprising a tubular hollow-casing and sound chambers in opencommunication therewith, a combined speaking and sound-transmitting unitin one of the sound chambers of each telephone unit, the said combinedspeaking and sound-transmitting unit comprising a fiat diaphragm, a wirecoil fixed to the diaphragm, permanent magnetic members in the chamberjuxtaposed relative to the wire coil so as to set up an intense magneticfield in which the wire coil may vibrate responsively to vibrations ofthe diaphragm for inducing a current in the coil, a pair of bindingposts diametrically oppositely mounted in the casing of the said soundchamber, oppositely extending conductors from the wire coil to thecasing attached to the binding posts, and leads passing from the bindingposts through the hollow casing for transmission of current induced inthe coil.

2. In a telephone system including a pair of telephone units, eachcomprising a tubular hollow casing, sound chambers in open communicationtherewith and sound-transmitting means in one of the sound chambers, thesaid soundtransmitting means including a combined speaking and receivingunit in one of the chambers of each telephone unit, the said unitincluding oppositely disposed fixed magnets including complementarypermanent magnetic brackets relatively disposed to form a substantiallyhollow rectangle but having ends of like polarity spaced apart but inadjacent relation, means rigidly connecting an adjacent pair of ends oflike polarity to the casing of the chamber with opposite pair of ends oflike polarity maintained freely spaced, a further permanent magnetic barunit interposed between the said magnetic brackets with ends of oppositepolarity relative to said pairs of ends of the magnetic bracketsdisposed in the space between the said magnetic brackets for closing andmaintaining a closed magnetic field around the brackets, the saidmagnetic bar unit having a free end disposed between the free pair ofends of the said magnetic brackets, the ends of the said magnetic barunit being adjacent to each pair of ends of the magnetic brackets but ofopposite polarity relative thereto, a flat diaphragm, means peripherallyholding the dia-- phragm, a wire coil carried by the diaphragm, an openspool medially mounted on the diaphragm and adapted to receive the freeend of the said magnetic bar unit, the wire coil being fixed to the saidspool and thereby positioned in the said magntic field, a pair ofbinding posts mounted in the casing of the sound chamber, oppositelyextending conductors from the wire coil to the casing attached to thebinding posts and leads passing from the binding posts through thehollow-casing for transmission of current induced in the coil.

CARL BECKMAN. IRVING ZAMIBAKIAN.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 230,924 Coombs Aug. 10, 18801,604,149 Dix Oct. 26, 1926 2,083,537 Abrahams June 15, 1937 2,098,402Reifsteck et al Nov. 9, 1937 2,109,761 Warnke Mar. 1, 1938 2,162,270Mott June 13, 1939 2,255,840 Woolf Sept. 16, 1941 FOREIGN PATENTS NumberCountry Date 374,946 Great Britain June 20, 1932

